Field of the Invention
The invention relates to a structure for connecting a plurality of mutually remote electrical components to a central unit, including a flexible printed circuit board having an inner region with contact surfaces for contacting connection contacts of the central unit, and individual conductor tracks having one end at the contact surfaces and another end for connection of the electrical components.
Such a structure is equivalent to an electrical connection between a hybrid component group and a flexible printed circuit board, which is known from German Published, Non-Prosecuted Patent Application DE 38 13 566 A1. That electrical connection includes two lines of conductors, each with a plurality of conductor tracks, which are exposed in the region of a cutout of the printed circuit board for contacting with contacts of the hybrid component group. The printed circuit board has holes by which it can be affixed to a substrate acting as a cooling body. Connection tracks constructed on free ends of the conductor tracks rest on contact surfaces of the hybrid component group and are electrically connected through the use of clip soldering processes.
In many applications, the problem arises of connecting a plurality of mutually remote electrical components to a central unit. The central unit may, for instance, be provided with a multiple plug by way of which the components can be connected to a central control unit or the like. One example of such an application is an automatic transmission, in which various sensors for detecting rotary speeds, pressures and temperatures are disposed, and which includes electric actuators for actuating couplings or switch elements.
It is known from German Published, Non-Prosecuted Patent Application DE 44 30 798 A1, corresponding to U.S. Pat. No. 5,831,835, filed Feb. 28, 1997, to construct the conductor tracks required for connecting the components to the central unit, in the form of a stamped grating, which, for instance, is formed of a copper alloy. The stamped grating is stamped out from a metal sheet or plate and incorporated into a support body inside the transmission housing. The stamped grating is additionally provided with a plastic covering to protect against short circuits caused by metal chips. Overall, the use of a stamped grating is relatively expensive, because of the requisite tool expense among other reasons.
The use of flexible printed circuit boards or flexible conductor films is also conventional for connecting a plurality of electrical components that are distant from one another. Such flexible printed circuit boards, for instance, are formed of a polyimide film or slab onto which a conductive copper layer is applied through the use of an adhesive, such as an acrylic adhesive, and the copper layer can in turn be coated with silver. Flexible printed circuit boards of that kind are made to be very supple without damage to the electrical conductor tracks. Another advantage is that the flexible printed circuit boards can be made oil-resistant, so that they can also be used inside transmission housings where they come into contact with transmission oil. However, the oil-resistant flexible printed circuit boards are relatively expensive, so that when used for the aforementioned purpose the surface area that is consumed is great. Overall, that leads to costs that are high, similarly to those involved in the use of stamped gratings.